The invention relates to a process for preparing vanillylamine hydrochloride which can be used on an industrial scale.
Vanillylamine hydrochloride is an intermediate product in the preparation of pelargonic acid vanillylamide, which is used as a hyperemia inducing active substance, e.g. in plasters.
German Patent DE 760 746 describes the preparation of vanillylamine hydrochloride, in which the isolated 4-hydroxy-3-methoxy-benzaldoxime used as starting material is reduced using hydrogen in the presence of activated charcoal and palladium oxide in an acetic acid solution and with the subsequent addition of hydrochloric acid to obtain the vanillylamine hydrochloride.
The preparation of 4-hydroxy-3-methoxy-benzaldoxime from vanillin and hydroxylamine hydrochloride in a basic medium is described in the literature (Ganett, P. M., J. Org. Chem. Vol. 53, No. 5, 1988). First, the oxime is isolated and then reduced to the amine in an ethanolic hydrochloric acid solution. The isolation of the oxime represents a significant expenditure of cost and time, particularly in the production of vanillylamine hydrochloride on an industrial scale.
The problem overcome by the present invention is therefore to prepare a cost effective process for preparing vanillylamine hydrochloride which can be used on an industrial scale.